1. Field of the Invention
The invention relates to a pipe clamp for connecting two pipes, in particular, pipes of a motor vehicle exhaust gas pipeline. The pipes can be inserted partially into one another and have an insertion end section and a receiving end section. The insertion end section is divided into two spherical zones of which the first spherical zone adjoining the free end of the insertion end section has an outer radius that is identical to the inner radius of the receiving end section. The receiving end section is also shaped as a spherical zone, and the insertion end section is insertable into the receiving end section. The second spherical zone of the insertion end section has an outer radius that is identical to the outer radius of the receiving end section. The pipe clamp comprises a clamp strap that can be placed about the receiving end section and the second spherical zone when the pipes are inserted into one another. The clamping strap is curved about a transverse axis that, when the pipes are coaxially inserted into one another and when the clamping strap is placed in the untightened state about the end sections of the pipes, is positioned in a center plane of the clamping strap that is perpendicular to the coaxial center axes of the pipes. The clamping strap comprises outwardly projecting clamping jaws. A clamping screw is inserted through holes in the clamping jaws. The clamping screw is supported with its head on a side of the first clamping jaw facing away from the second clamping jaw and with the other end on a side of the second clamping jaw facing away from the first clamping jaw by means of an intermediate part provided with a threaded bore engaged by the clamping screw.
2. Description of the Related Art
In known pipe clamps of the aforementioned kind, used in connection with exhaust gas pipelines of motor vehicles, the first spherical zone of the insertion end section engages the spherical zone of the receiving end section. The seal tightness of the pipe clamp is based only on a precise fit of the mutual contacting surfaces of the engaging spherical zones. The seal tightness is therefore insufficient when a high fluid pressure in the pipes is present. The clamping jaws are shaped in a similar way as the clamping jaws of the clamp according to DE 34 04 739 C1 and are connected to the clamping strap by spot welding. From the beginning, the clamping screw is curved approximately in accordance with the outer circumference of the pipes to be connected. If no curvature were provided, a contact of the clamping screw with the outer pipe surfaces could occur as a result of the support edges of the clamping jaws that, in the circumferential direction of the clamp, are positioned spaced far away from the clamp gap; this could lead to damage of the thread of the clamping screw. In an extreme situation, the clamping screw can bend when tightening the clamp; this can make tightening more difficult. Welding of the clamping jaws is not only complex but also damages a protective layer optionally provided on the clamping straps as a protection against corrosion. In addition, the welds must be subjected to a strength control.